I am pretty much exactly the same size as you, although I do have a wider chest. I've tried a few different options, but I've most liked the Alternative Apparel v-necks as undershirts. They're kind of expensive, but I got them on sale at Belle and Clive (where they were still kind of expensive). The V is deep enough not to show at all when the top button is undone. They come in a range of colors, so you can get something that isn't white, and won't show from under thin,...

People keep saying things like this, but I don't think it makes sense to match the color of your socks with anything worn on the top half of your body. Maybe they shouldn't clash, but to have the same color socks as tie or shirt or pocket square? Something about it seems not right, and I want to say because it seems overly-affected, or possibly too much like a costume.

If the waist were not too large, how could you pull up your trousers so much? The rise of the trousers would have prevented you from doing so without discomfort if the waist were small enough to keep them in the appropriate position.

I think what you mean by complimentary is what I mean by coordinate. And both terms are vague enough both to avoid the derogatory labels of "science" and "rules" and to encompass the less-noted aspects of coordination you mention.